1. Field of the Invention
The present invention relates to inflatable vehicular airbags. Specifically, the present invention relates to a deployment guide for use with inflatable vehicular airbags such as inflatable curtains.
2. Description of Related Art
In low-speed automobile collisions, occupants wearing safety belts are generally prevented from impact with objects located inside the vehicle such as the windshield, instrument panel, door, side windows, or steering wheel. In more severe collisions, however, even belted occupants may strike the interior of the car because their momentum is so great that they contact these objects before the seatbelts can fully decelerate them.
Conventional airbag systems were developed to supplement safety belts by deploying between an occupant and the interior surfaces of the vehicle. This reduces the chances of occupant contact with the vehicle""s interior. A conventional airbag system typically consists of several parts, including: an airbag cushion, a sensor, and an inflator. The airbag is typically made of a thin nylon fabric, which is folded to fit into a steering wheel, dashboard, roof rail, interior panel, dashboard, or other space in a vehicle. The airbag system is tuned to use sensors in the vehicle to detect the sudden deceleration characteristic of an impact of a predetermined intensity. When the system detects an impact of sufficient severity it sends an electrical signal to the inflator. The inflator then produces an inflation gas for filling the airbag cushion. The inflation gas is then channeled into the airbag, inflating it. When an occupant of the vehicle contacts the airbag, the airbag absorbs the force of the occupant""s impact. The inflation gas is then vented from openings in the airbag, eventually deflating it.
Airbags were first used in the front of a vehicle for an occupant""s safety. More recently, vehicle manufacturers and suppliers developed side-impact airbag systems to better protect vehicle occupants during side-impact collisions. These airbag systems, which are commonly referred to as xe2x80x9cinflatable curtains,xe2x80x9d are designed to inflate during an accident to cover the windows, doors, and lateral surfaces of the vehicle.
Inflatable curtain systems are often mounted within a housing located in the vehicle over the doors. Typically, this involves mounting the curtain along the edge of the roof of the vehicle behind interior trim such as a headliner, the A/B/C/D pillar trim, ATL""s, sun visors, grab handles, coat hangers, and even weather seals. Care must be taken when designing such mounting schemes to assure that when an airbag is inflated it is able to properly displace the headliner and deploy around the interior trim of the vehicle and deploy within the vehicle to be positioned to protect vehicle occupants.
During the deployment of the airbag, the inflating cushion expands by first moving into areas that provide the least resistance with the interior vehicle trim. When the internal pressure of the inflating airbag becomes sufficient to displace the interior trim, the airbag rapidly moves into the cabin of the vehicle and becomes fully inflated.
Several difficulties have been encountered in assuring that inflatable curtain airbags are properly deployed during a collision. First, in many vehicles there is a void space located behind the trim near the installed airbag. Such voids are often present at the top of the structural pillars or trim of the vehicle. Of specific note are the void spaces located at the tops of pillars such as the B, C, and D pillars. During airbag deployment, the expanding airbag sometimes fills these void spaces. When this happens, as the headliner gives way, those regions of the airbag cushion that have penetrated into the void spaces may be delayed in their deployment into the cabin. Indeed, the airbag as a whole or in part may become caught in the trim and thus be prevented from properly deploying. Lastly, the caught or misdirected airbag may continue to expand and eventually detach the trim from the vehicle, possibly sending it into the passenger compartment.
Additionally, in many vehicles, the pillar areas have a diverging flange to blend the shape of the pillar into the headliner surface to provide a more visually-pleasing appearance. An overlap space of at least 10 mm of the pillar over the headliner is often provided to assure that no gap will appear between them as a result of normal build variances. This overlap provides a further obstacle to the proper deployment of the airbag cushion.
These deployment problems have been addressed by adding deployment xe2x80x9crampsxe2x80x9d or xe2x80x9cguidesxe2x80x9d to direct a deploying airbag over void spaces and toward the headliner. Such deployment ramps are generally made of a solid material. The ramps are often up to 1-1xc2xd inches thick to provide sufficient resistance to direct the airbag to properly deploy through the headliner. Because of their size and shape, these ramps may complicate the airbag installation process. Additionally, the ramps add expense to the cost of airbag systems in vehicles and take up space behind the trim.
Accordingly, it would be an advancement in the art to provide an inflatable airbag deployment guide that is integrated into the inflatable curtain module. Additionally, it would be beneficial to provide a guide that is placed for use only when it is needed, such as during the deployment of the airbag. Further, it would be an advancement in the art to provide a deployment guide that takes up little space during storage, and adds little weight and expense to the inflatable curtain system. Such an airbag deployment guide is disclosed herein.
The apparatus of the present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available airbag deployment guides.
The invention provides a self-contained, compact, and inexpensive guide for the deployment of inflatable curtain airbag cushions. Specifically, the invention includes an inflatable guide for directing an airbag cushion over obstacles such as void spaces to assure proper deployment of the airbag. The inflatable deployment guide may be incorporated into airbags and airbag modules. The invention also includes methods of deploying an airbag cushion using such an inflatable guide.
The inflatable airbag deployment guide of the invention has an inflatable bladder that is typically attached to the outside (or vehicular window side) of an airbag cushion by an inflation inlet. The inflation inlet may be connected to an early-filling portion of the cushion. The bladder and inlet may be integrated into the weave design of the cushion, or they may each be cut and assembled separately. The inflatable bladder may also be included in an airbag module. As such, the inflatable bladder may be attached to the airbag, or may be attached directly to the inflator or to the inflator housing of the module instead of to the airbag.
As briefly noted, the airbag deployment guide also includes an inflation inlet. The inflation inlet allows inflation gas to pass from the airbag cushion or filling tube attached to the inflation device into the bladder of the inflatable airbag deployment guide. To do this, the inflation inlet may be coupled on a first end to an airbag cushion and on a second end to the inflatable bladder.
Generally, the uninflated bladder of the inflatable guide occupies little space, and can thus be housed inside the cover system of an existing airbag module. The guide may be configured such that when the airbag module is properly installed in a vehicle, it is positioned near the void space in the trim. This places the guide in position for proper deployment during a collision event.
Upon deployment of the inflatable curtain, a portion of the gas moving into the airbag cushion is channeled into the inflatable bladder. This may be accomplished either by making the inflation inlet of the inflatable bladder continuous with the interior of the airbag cushion or by directly attaching the inflation inlet to an opening of the inflator or inflator housing. In either case, the bladder is rapidly filled by the gas from the inflator.
The bladder prevents entry of the airbag cushion into voids in the trim. To do this the bladder may be sized to take up all of the available space in the void area in the trim. The bladder would thus prevent penetration of the airbag cushion into the void space by occupying the space and providing resistance to the expanding cushion. Alternatively, the bladder may be sized to inflate sufficiently to merely cover over the void space. In this way, the bladder blocks the airbag cushion from accessing the void space during the deployment of the airbag. In still other alternatives, the inflatable bladder is sized to inflate and simply bridge over at least a portion of the void space.
In use, the inflatable bladder deploys into or across the void space while the airbag cushion continues to fill. As the airbag cushion begins to inflate and push down out of its stored location, the filled inflatable bladder resists the force exerted upon it by the inflating airbag cushion. This prevents the airbag cushion from xe2x80x9cseeingxe2x80x9d any void in the trim void space as a path of least resistance. The airbag cushion thus inflates until it escapes through the headliner over the trim edge and out into the vehicle cabin.
The bladder is configured to inflate either before the airbag cushion or very early in the inflation of the airbag cushion. Due to the shape and size of the bladder, as well as its proximity to an inflator, the inflatable bladder inflates rapidly. The inflatable bladder is configured to inflate, hold pressure to assure proper deployment of the airbag, and then remain inflated for the same time period as the rest of the cushion. The inflatable bladder then deflates with the rest of the module.
The invention also includes methods of guiding the deployment of any airbag cushion by placing an inflatable structure in the path of the airbag cushion. Such methods may include the steps of inflating an inflatable bladder in a void located near an airbag cushion and inflating the airbag cushion. When inflated, the airbag deployment guide promotes proper inflation of the airbag cushion. In these methods, the bladder and the airbag cushion may be inflated at substantially the same time, or the bladder may be inflated before the airbag cushion.
These and other features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.